Everyone expects stability from software systems. At the same time we expect to be able to deploy features frequently.

Every such deployment - by definition - introduces instability while the change is being deployed. Is this a conflict that can be solved?

In this talk we will guide you through our team journey towards maintaining Reliability and Stability of a ever changing system built from dozens of micro services supporting critical Tier 0 Tesco Identity Service.

We will present how we tackled this problem relying on our Team Culture involving processes and procedures, as well as solutions like Observability, Alerts, Deployment Automation and Certificate Management. We will not offer a silver bullet to kill a chaos daemon. Instead we will present pros and cons of the solutions we carefully selected to improve stability in our system.